U.S. patent number 6,188,945 [Application Number 08/937,253] was granted by the patent office on 2001-02-13 for drive train control for a motor vehicle.
This patent grant is currently assigned to Siemens Aktiengesellschaft. Invention is credited to Friedrich Graf, Gregor Probst, Roman Strasser.
United States Patent |
6,188,945 |
Graf , et al. |
February 13, 2001 |
Drive train control for a motor vehicle
Abstract
An integrated drive train control system for a motor vehicle
interprets the position of the accelerator pedal and the brake
pedal as a wheel torque desired by the driver. A calculating device
receives signals representing the positions of the accelerator
pedal and the brake pedal. Central control parameters for the drive
sources and for the decelerating units of the drive train are
generated on the basis of the position signals. A classification
device evaluates the sensor signals from the drive train and
classifies operating parameters of the motor vehicle.
Inventors: |
Graf; Friedrich (Regensburg,
DE), Probst; Gregor (Landshut, DE),
Strasser; Roman (Burgkirchen, DE) |
Assignee: |
Siemens Aktiengesellschaft
(Munich, DE)
|
Family
ID: |
7805453 |
Appl.
No.: |
08/937,253 |
Filed: |
September 12, 1997 |
Foreign Application Priority Data
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Sep 12, 1996 [DE] |
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196 37 210 |
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Current U.S.
Class: |
701/58; 701/54;
180/65.27 |
Current CPC
Class: |
B60W
30/188 (20130101); B60T 8/175 (20130101); B60K
31/0058 (20130101); B60T 2220/02 (20130101); B60W
2050/0057 (20130101); F16H 59/44 (20130101); B60W
2710/105 (20130101); F16H 59/18 (20130101); B60W
2556/50 (20200201); F16H 59/24 (20130101); B60W
2530/00 (20130101); B60W 40/09 (20130101); B60T
2260/08 (20130101); F16H 2061/0081 (20130101); B60W
2540/30 (20130101); F16H 59/54 (20130101); B60L
2240/486 (20130101) |
Current International
Class: |
B60K
6/04 (20060101); B60K 6/00 (20060101); B60T
8/17 (20060101); B60T 8/175 (20060101); B60K
31/00 (20060101); F16H 59/18 (20060101); F16H
59/44 (20060101); F16H 59/24 (20060101); F16H
59/50 (20060101); F16H 59/54 (20060101); F16H
61/00 (20060101); B60K 041/04 (); F02D
028/00 () |
Field of
Search: |
;701/51,58,60,61,54,53,48,57 ;180/65.2 ;477/20,107,109,110 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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4039005A1 |
|
Jun 1991 |
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DE |
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4401416A1 |
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Jul 1995 |
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DE |
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0388107 |
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Sep 1990 |
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EP |
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0576703A1 |
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Jan 1994 |
|
EP |
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2 031 822 |
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Apr 1980 |
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GB |
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2240827 |
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Aug 1991 |
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GB |
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2255057 |
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Oct 1992 |
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GB |
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Other References
International Applicatio WO 90/03898 (Lang), dated Apr. 19, 1990.
.
"Systemvernetzung im Automobil", R. Leonhard, Stuttgart,
Feinwerkstechnik im Fahrzeugbau, Munchen, 1993, pp. 87-90. .
"Fahrzeugregelung und regelungstechnische Komponentenabstimmung",
U. Zoelch et al., VDM Berichte No. 1225, 1995, pp. 281-297,
pertains to motor vehicle control and closed-loop/open-loop control
adjustment..
|
Primary Examiner: Zanelli; Michael J.
Attorney, Agent or Firm: Lerner; Herbert L. Greenberg;
Laurence A. Stemer; Werner H.
Claims
We claim:
1. A drive train control system for a motor vehicle having an
engine, a transmission, wheels, an accelerator pedal, and a brake
pedal, the drive train control system comprising:
a calculating device connected to receive position signals
representing a position of the accelerator pedal and a position of
the brake pedal, said calculating device interpreting the position
of the accelerator pedal as one of a wheel torque and a
transmission output torque desired by a driver of the motor vehicle
independent of transmission and engine-specific parameters and
calculating therefrom setpoint values for the engine and the
transmission of the motor vehicle;
a classification device connected to receive sensor signals from
the drive train, said classification device being programmed to
evaluate the sensor signals and to classify operating parameters of
the motor vehicle; and
said calculating device combining the position signals and the
classified operating parameters and generating therefrom central
control parameters for drive sources and decelerating units of the
drive train of the motor vehicle.
2. The drive train control system according to claim 1, wherein
said calculating device is programmed to adjust a transmission
ratio in the transmission.
3. The drive train control system according to claim 1, wherein
said calculating device is programmed to adjust an engine
torque.
4. The drive train control system according to claim 1, wherein
said calculating device is programmed to define a type of drive
source of the motor vehicle.
5. The drive train control system according to claim 1, wherein the
engine is a hybrid drive, and said calculating device is programmed
to define and adjust individual operating points of the hybrid
drive.
6. The drive train control system according to claim 5, wherein
said calculating device is programmed to adjust an engine torque as
a function of the transmission ratio of the hybrid drive.
7. The drive train control system according to claim 1, which
further comprises:
a selection circuit connected to receive output signals of said
classification circuit, said selection circuit selecting a driving
strategy based on the output signals of said classification
circuit; and
decentralized control units connected to receive output signals of
said calculating device and of said selection circuit, said
decentralized control units generating control signals for the
engine, the transmission and a brake system of the motor
vehicle.
8. The drive train control according to claim 7, wherein a data
exchange among said control units is effected in a torque-based
manner.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a drive train control system for a motor
vehicle, by which the position of the accelerator pedal is
interpreted as a wheel torque or transmission output torque desired
by the driver and used for calculating desired values for the
engine and transmission of the motor vehicle.
Prior art control systems for the engine, for the transmission, and
for the secondary assemblies of a motor vehicle operate largely
independently; that is, they establish the operating point and
operating mode of the controlled assembly largely independently of
one another. Means are also available for communication among the
various components of the drive train of a motor vehicle, for
instance in the form of a CAN bus or the like, but these means are
predominantly used only for exchanging sensor data in the course of
multiple utilization. Moreover, the control systems affect one
another by means of communication in certain operations, for
instance to make for smoother shifting by reducing the engine
torque upon a change of transmission ratio in the transmission.
Other examples are engine drag torque control during braking and
braking intervention or torque reduction if drive slip arises in
the traction control context. A system for linking together systems
in the automobile has become known heretofore that seeks an
integrated drive train control system for a motor vehicle by means
of which the position of the accelerator pedal is interpreted as a
wheel torque desired by the driver and used for calculating desired
values for the engine and transmission of the motor vehicle (F
& M 101 (1993) 3, pp. 87-90). The goal of the overriding
optimization, proposed in this publication, of the parts of the
system embodied by the engine control unit, electronic accelerator
pedal and transmission control unit, is to reduce fuel consumption
and improve the drivability, in particular with regard to the
spontaneous reaction to movements of the accelerator pedal.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a drive
train control for a motor vehicle, which overcomes the
above-mentioned disadvantages of the heretofore-known devices and
methods of this general type and which globally improves the
operation of the motor vehicle. Emissions (hydrocarbons, nitrogen
oxides, etc.) are to be minimized by centrally defining a strategy
for the engine control, engine performance adjuster and
transmission control, that minimizes the emission of pollutants,
especially in urban areas. The central strategy may also have as
its goal a performance-oriented mode of the motor vehicle. In such
a strategy, all the decentralized function units are adjusted in
such a way that the best possible acceleration and rapid response
of the drive to driver demands are available. Such a mode is
required in a sporty driving mode and in driving uphill.
With the foregoing and other objects in view there is provided, in
accordance with the invention, a drive train control system for a
motor vehicle having an engine, a transmission, wheels, an
accelerator pedal, and a brake pedal, the drive train control
system comprising:
a calculating device connected to receive position signals
representing a position of the accelerator pedal and a position of
the brake pedal, the calculating device interpreting the position
of the accelerator pedal as a wheel torque or transmission output
torque desired by a driver of the motor vehicle and calculating
therefrom setpoint values for the engine and the transmission of
the motor vehicle;
a classification device connected to receive sensor signals from
the drive train, the classification device being programmed to
evaluate the sensor signals and to classify operating parameters of
the motor vehicle; and
the calculating device combining the position signals and the
classified operating parameters and generating therefrom central
control parameters for drive sources and decelerating units of the
drive train of the motor vehicle.
In accordance with an added feature of the invention, the
calculating device is programmed to adjust a transmission ratio in
the transmission.
In accordance with an additional feature of the invention, the
calculating device adjusts the engine output torque.
In accordance with another feature of the invention, the
calculating device defines a type of drive source of the motor
vehicle. Where the engine is a hybrid drive, the calculating device
defines and adjusts individual operating points of the hybrid
drive.
In accordance with a further feature of the invention, the
calculating device adjusts the engine torque as a function of the
transmission ratio of the hybrid drive.
In accordance with again a further feature of the invention, the
system further includes:
a selection circuit connected to receive output signals of the
classification circuit, the selection circuit selecting a driving
strategy based on the output signals of the classification circuit;
and decentralized control units connected to receive output signals
of the calculating device and of the selection circuit, the
decentralized control units generating control signals for the
engine, the transmission and a brake system of the motor
vehicle.
In accordance with a concomitant feature of the invention, a data
exchange among the control units is effected in a torque-based
manner.
Other features which are considered as characteristic for the
invention are set forth in the appended claims.
Although the invention is illustrated and described herein as
embodied in a drive train control system for a motor vehicle, it is
nevertheless not intended to be limited to the details shown, since
various modifications and structural changes may be made therein
without departing from the spirit of the invention and within the
scope and range of equivalents of the claims.
The construction and method of operation of the invention, however,
together with additional objects and advantages thereof will be
best understood from the following description of specific
embodiments when read in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing the hierarchical structure or
architecture of an integrated drive train control system according
to the invention;
FIG. 2 is a diagrammatic/schematic view of an integrated drive
train control system according to the invention;
FIG. 3 is a block diagram showing the control of the engine and
transmission with another embodiment of the drive train control
system;
FIG. 4 is a flowchart of the program processed by the drive train
control system of FIG. 2; and
FIG. 5 is a partial flow chart of a subroutine in the process of
the flowchart of FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the figures of the drawing in detail and first,
particularly, to FIG. 1 thereof, there is seen an integrated drive
train control system 1. For the sake of better readability, the
terms "circuit" or "block" will often be omitted for the individual
circuit or program components (for example, selector rather than
selection circuit).
The components are as follows: sensors 1.01, combined symbolically
into one block; a central unit for classification and criteria
formation 1.02; a central unit for determining operating parameters
1.03, which receives the signals from the accelerator pedal and the
brake pedal of the motor vehicle; a driving strategy selector 1.04;
decentralized control units 1.05 combined in a block; and the
assemblies 1.06 of the drive train to be controlled, for example
the engine, the transmission, and the brakes of the motor
vehicle.
The function and the mode of operation of the components of FIG. 1
will now be described in conjunction with the description of the
other drawing figures.
The integrated drive train control system 1 is shown in more detail
in FIG. 2. It has the following components in the central
classification and criteria formation block 1.02: a driver type and
driver demand determining circuit 2, an environment type and road
type localization unit 3 (for example via GPS), a driving maneuver
and driving situation detection unit 4, and an information channel
5 (for instance, a car phone or a satellite receiver). The circuits
2-5 and other circuit components to be described below in the drive
train control system 1 are supplied with the signals from various
sensors in the motor vehicle, here symbolically represented by the
letter S, over suitable signals lines. The signal lines are shown
in the drawing as multiple lines but may also be embodied as a data
bus (such as a CAN bus).
A basic driving strategy selector 6, via lines 14-18, receives
output signals from the aforementioned circuits 2-5. Via a line 19,
it receives the output signal of a wheel torque calculation device
12, which in turn receives signals from a brake pedal 20 and an
accelerator pedal or gas pedal 21.
Output signals from the basic driving strategy selector 6 are
delivered to a basic operating parameters determining unit 7 and to
an electronic engine controller and engine performance adjusting
unit 9. (The term "unit" as used herein does not necessarily
require a separate component, but it also encompasses functional
subroutines and circuit components.) The output signals of the unit
7 proceed to a driver information block or display 16, an
electrical power steering system (EPAS) 8, an electronic engine
control system (EMS/ETC) 9, an electronic transmission control
(EGS) 10, and a brake controller 11, which can include an ABS
system, a traction control system TCS, and a driving stability
control system FSR.
The basic operating parameters determining unit (or block) 7 now,
in accordance with the strategy specification from block 6, carries
out a coordinated calculation of the central operating parameters
of the entire drive train. In the block 6, the transmission ratios
and the desired engine torque are for instance defined, but also
the drive type and in the case of a hybrid drive its individual
operating points as well. This enables a substantially more
comprehensive control of the engine and transmission than before.
Thus the engine torque can be adjusted as a function of the
transmission ratio. This increases the drivability of the motor
vehicle, since the driver on upshifting no longer has to compensate
for a loss of output torque. In addition, and quite importantly,
pollutant emissions can be effectively reduced as well (as will be
explained later herein).
The coordinated definition of the operating parameters of the
engine and transmission takes place not only in a steady state,
i.e., not only at a constant wheel torque demand from block 12.
Information on dynamic events, such as cornering or a transition to
the overrunning mode (the vehicle speed is reduced), is taken into
account by the block 7 as well, in order to coordinate the function
units 8-11 that follow it. For instance, in the case of
overrunning, the current transmission ratio can be retained and at
the same time the overrunning shutoff can be activated. In
cornering on extremely sharp curves, it is appropriate, in order to
maintain driving stability, that the transmission ratio be fixed
(see EGS) and that load changes in the drive train be damped or
made to proceed more slowly (see EMS/ETC).
The centralization along the lines of drive mode management and
emissions management should be done only as much as necessary,
however (strategy specification and/or delegation). All the other
functions (such as functions for driving stability) proceed as much
as possible at the level of the decentralized control units.
The control circuits or units 8-11 produce adjusting signals with
which the individual assemblies or components of the drive train 24
of the motor vehicle are controlled, that is, the engine via its
throttle valve, the transmission, and the brakes of the motor
vehicle. The adjusting signals pass over lines A from the circuits
9-11 to the assemblies of the drive train; sensor signals S are
carried over corresponding lines to the aforementioned circuits.
The control circuits or units 8-11 may, however, also be put
together as so-called on-site units with whichever assembly is to
be controlled, or can be integrated with it. For instance, it is
appropriate for the controller 11, especially in the case of an
electrical brake actuator, to be combined with the brake actuator.
This changes nothing in terms of the control function.
The individual components of the drive train itself are shown
toward the bottom of FIG. 2 and will not be explained further here
because they are well known. In the case of a hybrid drive--that
is, an internal combustion engine combined with an electric
motor--the former is coupled to an electric motor and a generator
G. One such hybrid drive is known, for instance, from VDI-Bericht
[VDI Report; VDI=Association of German Engineers] No. 1225, 1995,
pp. 281, 297.
Examples of a global or combined drive train control system
according to the invention are as follows:
1. A minimized emissions mode (HC, NO.sub.x):
The basic driving strategy selector 6 defines the operating mode of
the entire drive train for minimized pollutant emissions.
From this specification, a central "decider", that is, the basic
driving strategy selector 6, defines the essential operating
parameters of circuits 9, 10 (EMS, ETC, EGS) such that pollutant
emissions are minimized (for instance in urban areas). This
specification can be converted by the following function units as
follows:
ETC (electronic engine performance controller): load changes of the
engine are damped (demanded by unit 12), or the operating range is
restricted. By avoiding non-steady-state events, closed- and
open-looped control systems that seek a reduction in emissions can
operate without error. Operating ranges with quantitatively or
qualitatively undesired emissions composition are avoided.
EMS (electronic engine control): activation of a low-emissions
mode, for instance in the engine by reducing fuel enrichment upon
acceleration, or changing the drive type (for instance to electric
motor, hydrogen drive)
EGS (electronic transmission control): brings about the most
steady-state operation mode possible for the engine in a range with
minimum emissions, for instance with CVT or in a many-geared
transmission;
adaptation if there is a change of drive type (such as electric
motor, hydrogen drive, coordinated by unit 7): particularly in this
function, good cooperation of engine and transmission is important,
because the driver demand with regard to acceleration and speed
allows more combinations of resultant engine torque and
transmission ratio. An adapted course of the change over time in
the two controlling variables is also necessary.
2. A performance-oriented mode.
Analogously to the minimized emissions mode, all the decentralized
function units are adjusted such that the best possible
acceleration and rapid response of the drive train to driver
demands (unrestricted drive type) are available. This is necessary
in the sporty driving mode or in driving uphill.
FIG. 1 shows the architecture of such a functional layout.
However, decisions at lower control levels that affect higher
specifications are signaled as much as necessary to the higher
control levels. But this will also be explained in conjunction with
FIG. 2, whose function will now be explained in detail.
The block (or circuit) 2 serves to determine the driver type, that
is, to make a classification expressing a distinction between
performance-oriented and economy modes. One example of such a
function is described in European Patent Disclosure EP 0 576 703
A1. A signal characterizing the driving style of the driver is
delivered to a basic driving strategy selector 6 via a line 14.
Block 3 ascertains the road type (city/expressway/highway/country
road), but also can determine the general degree of air pollution,
for instance, via additional sensors. If the specific location of
the vehicle is known by GPS (global positioning system) in
conjunction with a digital card (on CD ROM), then this information
on the local air pollution can be made available to the block
6.
A detection, performed in block 4, of individual driving maneuvers,
such as cornering, an uphill grade, drive and brake slip, and
information on longitudinal and transverse stability can also be
utilized to ascertain the driving strategy choice. This information
can also be made available to block 7, so that by way of the
medium-term operating strategy it is also possible in the short
term to achieve a suitable operating mode of the drive train. This
information for blocks 6 and 7 can also originate in decentralized
control units (for instance, information on the dynamic driving
stability from the ABS/TCS/FSR control unit 11) or from the
information channel 5. Block 5 furnishes information that is
supplied by a central "control point", such as a traffic monitoring
agency. This makes regional, centralized control of low-emissions
operating modes possible.
Block 6 serves to ascertain the choice of basic driving strategy
for the following unit 7, which in turn in coordinated fashion
ascertains the central operating parameters for the decentralized
control units. The information on the lines 14, 15, 17 and 18 is
compared with a fixed set of rules. This is accomplished with a
fuzzy system, mathematically formulated algorithms, or a neural
network.
The sensors S furnish necessary signals both for forming the
classification and criteria in the top most layer of the drive
train control system 1, that is, in the units 2-5, and for the
decentralized control units for the individual assemblies. The
location of the sensors with regard to the function blocks plays a
subsidiary role, as long as communications between the sensor
signal processing in the respective control unit (ECU) and the
information sink are assured. Nor does it matter, with regard to
the functional architecture, which function units are physically
located in which ECU and combined with it. Thus it is entirely
possible to integrate the driver type and driver demand determining
unit in the transmission control system (EGS) 10, while the
environmental and road type classification can be accommodated in
block 11 (regulation of longitudinal and transverse dynamics).
A central computer can also contain the units 12, 6, 7. What is
essential is the virtual architecture, as shown in FIG. 2, for
attaining overall improved function. An important role is played
here by the communications between the physical units, which are
expediently embodied in the form of fast serial bus communication
(for instance via a CAN bus).
The specifications by the driver expressed through the accelerator
pedal or gas pedal are converted in block 12 into a desired wheel
torque specification, that is, the torque that is to be transmitted
from the drive wheels to the roadway. The influence of
environmentally dictated factors, such as additional driving
resistance (mountain driving, vehicle load), are not meant to be
taken into account here, so as not to alienate the driver from the
physical reality.
Block 12 is shown separately in FIG. 2, but it can also be
accommodated physically in the decentralized control units 8-11 or
16 (for instance in EMS/ETC). The same is true for locks 1-7. The
signal on line 19 can be output as a wheel torque desired by the
driver, or as a desired circumferential wheel force or a desired
transmission output torque. By means of continuous information via
the brake pedal 20, it is also possible to specify negative desired
wheel torques or desired circumferential wheel forces. Hence
integrated management of driving units (such as the engine,
electric motor, rotating flywheel) or decelerating units that
absorb energy (such as the service brake, generator, or a flywheel
not in motion) are possible. As an alternative to driver
specification of the wheel torque, this wheel torque can also be
specified by a cruise control 23 (FGR for short).
The information channels between block 7 ("basic operating
parameter determination") and the units 9, 10 and 11 can be used
bidirectionally. The reason for this is the necessity, in the
calculation of the basic operating parameters, of using not only
such external conditions as driver type, environment and driving
maneuvers as the basis but also of taking into account internal
specified operating states of the controlled units in the drive
train. For instance, it is important after a cold start to run the
engine at elevated rpm in order to reinforce the warmup of the
catalytic converter. Moreover, additional heat sources (such as an
electrically heated catalytic converter) represent an additional
load on the engine output. Adjusting the ignition timing toward
"late" after a cold start (optionally blowing in secondary air) for
the same purpose changes the characteristics of the drive train and
must be taken into account by the unit 7 (for instance, by
postponing gear shifting points to higher engine rpm levels).
A particular operating state in the transmission can likewise
affect the calculation of the transmission ratio (such as cold
transmission fluid when the torque converter lock up is turned on;
at excess transmission temperature, it is appropriate to shift
engine rpm levels to ranges that increase the volumetric throughput
of the oil pump of the transmission through the oil cooler). Other
interventions in the engine torque, such as increasing it in order
to compensate for the loss of torque by the air conditioning
compressor or losses of efficiency in the transmission (CVT:
adjusting the transmission ratio dictates a greater pumping power),
take place on the control level represented by blocks 8-11, unless
they also have to be supported by other provisions in block 7.
By means of the drive train control system of the invention, it is
thus possible not only for the gear shifting behavior, when driving
uphill and downhill or if performance demands oriented to driving
style and driving situation are made, but also the control of the
entire drive train, including the drive sources, to be subjected to
different criteria and adapted to them.
For instance it may be appropriate and necessary, in critical
situations and driving maneuvers, to adapt the current transmission
ratio (keep it unchanged) in a situation-oriented way, specifically
regardless of whatever general strategy has just been set. Such
dynamic corrections are functionally combined, in the control
concept of the invention, with the control of the engine (one
example is the coordinated lock up of a gear and activation of the
engine overrunning shutoff).
It is appropriate not yet to include engine-specific parameters in
block 12 (wheel torque calculation), because after all, in a hybrid
drive, for instance, the choice of driving type is not yet fixed at
this decision level. However, it is useful to include such
conditions as traction conditions (winter driving, a gravel road)
and above all in highly motorized vehicles preventively to reduce
the sensitivity of the system somewhat (to generate less wheel
torque with the accelerator pedal in the same position). In
general, the conversion of the accelerator pedal position into a
wheel torque can be done with a fuzzy system, which combines the
multiple dependencies into a desired wheel torque.
The advantages of the invention also reside in an integrated wheel
torque management, which processes the wheel torque as a negative
value as well and that influences both drive sources and the units
that slow down the vehicle. It is especially simple to couple it
with brake systems that have electrical brake actuation ("brake by
wire").
In block 7, not only the transmission ratios and the respective
desired engine torque but also the driving type and the individual
operating points thereof are defined. Not only is a strictly wheel
torque-oriented mode by driver specification possible, but by
centralized specifications in terms of pollutant emissions, the
real wheel torque can also be varied or limited. However, such
interventions must be displayed to the driver through block 16 and
must be done as much as possible without restrictions to drive mode
selection.
Blocks 2-7 and 12-16 may be accommodated in independent physical
units (control units) or can be integrated with the units 8-11.
This flexibility is yet another advantage of the invention.
The data exchange among the individual control units is done in
torque-based fashion. The term "torque-based" is understood as
follows: If the transmission demands a reduction in engine torque,
for instance, then it forwards a variable to the engine controller,
which represents the desired torque or in other words the desired
engine torque and does not for instance demand an ignition angle
reduction by 5%. Conversely, to ascertain the engine torque at the
current operating point, for instance of the transmission
controller, it is not the throttle valve position and engine rpm
that are transmitted, from which the transmission controller could
ascertain the current engine torque via a matrix stored in memory
in the transmission controller; instead the engine controller, via
an interface (such as CAN), transmits the current engine torque to
the transmission controller.
From FIG. 3, a somewhat simplified integrated drive train control 1
can be seen, which is used to control an internal combustion engine
and a transmission. The individual reference numerals correspond to
those of FIG. 2 but to distinguish them are followed by an asterisk
(*). The function of this drive train control is equivalent to that
described above to the extent that the same components are
present.
FIGS. 4 and 5 show a flowchart for the sequence performed by the
drive train control system 1 of the invention. After the Start A,
the program executes the following steps S1-S11:
S1 The cruise control FGR is activated, if desired.
S2 The information on the accelerator pedal--or the brake pedal--is
converted into a desired wheel torque (block 12). The cruise
control is optionally included.
S3 The driver, environment and driving maneuvers are classified or
detected (in blocks 1, 3 and 4).
S4 An inquiry of the information conduit 5 is made (in block
6).
S5 A basic driving strategy is chosen in block 6.
S6 The basic operating parameters for the drive train are chosen
(in block 7): the drive or deceleration source, the calculation of
operating points of the drive and delay sources, the calculation of
the operating point of the transmission (in block 7).
S7 The driving stability is monitored: with ABS, engine performance
adjuster TCS, and driving stability controller FSR. The desired
braking torque is established.
S8 The question is asked whether a driving stability intervention
should be made (in block 7 or 9), if so, then in
S9 the drive torque or brake torque is corrected in the drive
(block 7 or 9). If not, then in a step
S10 The question is asked whether there is a loss of efficiency in
the drive train. If so, then in a step
S11 The drive performance is increased. After that, and also if the
answer is no, the program proceeds to its END
Step S6 can also be in the form of a subroutine having the
following steps (FIG. 5):
S6.1 The steady-state parameters of the drive and transmission are
calculated (based on performance graphs, an algorithm, a fuzzy
system, or a strategy specification).
S6.2 A temporary intervention in the drive and the transmission is
calculated, specifically as a function of the driving situation and
the driving maneuvers, for instance upon gear lockup when
overrunning or conditions of brake assist.
The program is subsequently processed to its end as explained in
conjunction with FIG. 4.
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